Arsenal and Diggle confront Laurel about trying to step into her sister’s shoes and warn her to stop before she gets herself killed. However, when Brick kidnaps the city’s Aldermen and threatens to kill them all unless the police evacuate The Glades, it’s all suits on deck. Meanwhile, Ray steps in to help Lance and the police force fight Brick, showing Felicity a new side of her boss. Malcom tells Thea that Ra’s al Ghul is after him and his family and they must leave town immediately.
Peggy may be in more trouble than usual when fugitive Howard Stark suddenly returns for mysterious reasons. And Chief Dooley chases a new clue all the way to Europe that threatens to destroy Peggy’s future at the SSR.
Dr. Wells’ former protégée, Hartley Rathaway, returns to seek revenge on his mentor after being affected by the particle accelerator explosion. Now able to manipulate sound waves, the brilliant Rathaway is a dangerous threat to both Wells and The Flash. Meanwhile, Iris is thrilled when she’s hired by the Central City Picture News as their newest cub reporter. Unfortunately, her editor pairs her with a veteran reporter, Mason Bridge, who wants nothing to do with her. Cisco recalls his first day on the job at S.T.A.R. Labs when he met Hartley and Caitlin. Joe asks Eddie for a favor but asks him to keep it a secret from Barry.
Marty and Jeannie pitch opposing strategies to a Seattle-based skin care company. Doug, fed up with Sarah’s antics, passive-aggressively puts his foot down. Clyde begins discussing a business idea with an unlikely partner.
Clarke strikes a deal with Lexa and Indra. Abby and Kane begin to realize that decision making powers are out of their hands. A seething Raven is unable to control her emotions. A bold move threatens to destroy the newly formed alliance between the sky people and the Grounders, and a familiar face haunts Clarke. Meanwhile, back at Mount Weather, Monty comes up with a risky plan.
Jane worries for Lisbon’s safety when the team puts itself in the line of fire to protect the witness in a murder investigation from a skilled assassin.
In the aftermath of Oliver’s fight with Ra’s al Ghul, Diggle and Arsenal continue to protect the city in the Arrow’s absence. However, after three days without hearing from Oliver, they begin to fear the worst may have happened to their friend. Felicity refuses to believe that Oliver could be dead until Merlyn pays the team a surprise visit. Thea suspects there is something more behind Oliver’s disappearance and asks Merlyn for a favor. Meanwhile, Ray tests a part of his new suit and Laurel takes up the mantle of the Black Canary.
Leonard Snart AKA Captain Cold returns to Central City with a new hotheaded partner in tow – Mick Rory AKA Heat Wave. The duo plan to steal a multi-million dollar painting, but Cold has another agenda while in town – to set a trap for The Flash. Snart and Mick kidnap someone close to The Flash and threaten to kill them unless The Flash shows up for a battle of fire and ice. Barry tells Joe he isn’t sure he should take on Snart again after the casualties that happened the last time they fought. Meanwhile, Barry asks Dr. Wells, Caitlin and Cisco to help him double his training efforts so he’s ready for the Reverse Flash when he returns to Central City. Iris deals with the aftermath of Barry’s confession, and Cisco makes the CCPD a new shield.
When a young Latin telenovela actress is murdered, Beckett and the team delve into a case that is as flamboyant and full of intrigue as any telenovela. Meanwhile, Castle is hired as private investigator by the show’s sultry star to pursue the case from another angle.
Marty cunningly proves his business savvy when he meets electric car mogul, Ellis Hightower. In desperate pursuit of a new client, Jeannie orchestrates a chance encounter that appears to go terribly awry. Marty accuses Jeannie of being a dishonest person, prompting her to reveal a difficult truth.